There is unanimous agreement among the NHLBI Percutaneous Transiluminal Coronary Angioplasty (PTCA) Registry investigators, who are among the pioneers and the best qualified invasive cardiologists, that 10-year follow-up of the 2433 patients in the 1985-86 cohort is imperative. Clinical and angiographic characteristics as well as procedural details on both patient and lesion levels have been carefully measured and documented in this cohort. Data on the clinical status and anatomical changes in the coronaries have been updated annually or whenever repeat procedures were performed. PTCA in 1985-86 was carried out by techniques that are still current. Since then refinements have been made, but these have had only minimal effect on success and complication rates. Symptomatic and anatomical disease characteristics are similar to those of patients who are undergoing PTCA today. For these reasons extended follow-up information will be relevant to therapeutic decisions in the 1990s. A major motivation for the extended follow-up is the lesson learned from bypass surgery studies that documented an increased frequency of loss of therapeutic efficacy beginning 5-7 years after the operation. With 10-years experience and dedication to the evaluation of PTCA our Coordinating Center has an excellent track record in collaboration with the 16 Registry clinical sites. Over 95% follow-up rate has been maintained. Scientific reports are regularly disseminated to, and well received by, the cardiology community. In order to keep abreast with other percutaneous coronary intervention options, we recently established a Registry of new devices. By the end of the proposed follow-up, investigators of both Registries will be in the position to integrate what was learned. Currently, it is not expected that new devices will replace the role of PTCA in percutaneous coronary revascularization. Furthermore, the results will complement those which will become available in the 5-year follow-up of patients treated with PTCA or CABG in the Bypass Angioplasty Revascularization Investigation. Thus far the Registry has established that 4 years after PTCA, the mortality rate was 6% for successfully dilated patients. Thirty-five percent required repeat revascularization of which 11% was with bypass surgery. Over 75% of patients were asymptomatic four years after PTCA regardless of initial success.